Filter



W- D- MQUNT FILTER led May 5 3 Sheets-Sh et l 57 INVENTOR as W/LL MW 0. Amy yr ATTORNEYS.

a s. Era/IA 1,558,038 W. D. MOUNT FILTER Filed May 3, 1923 3 Sheets-Sheet 2 Oct. 20, 1925- A TTORN E YS.

W. D. MOUNT FILTER 3 Shoots-Shoot 5 INVENTOR.

W/ZA/fl/V .0. Mom r ATTORNEYS.

Patented Oct. 20, 1925.

UNITED STATES PATENT OFFICE.

WILLIAM D. MOUNT, OF LYNCHBURG, VIRGINIA, ASSIGNOR OF ONE-HALF TO JOSEPH E. MOUNT, OF ITHACA. NEW YORK.

FILTER.

Application filed May 3,

To all whom it may concern.

Be it known that I, WILLIAM D. MoUN'r, a citizen of the United States. residing at. Lynchburg, in the county of Campbell and State of Virginia. have invented certain new and useful Improvements in Filters. of which the following is a full, clear, and exact description.

This invention relates to filtering devices and particularly to rotary or continuous suction filters for separating solid particles from a carrier liquid. With such filters the formation of the filter cake is a progressive action. the cake becoming iirogressivcly thicker as the drum or filter surface travels through or in contact with the magma being filtered. reaching its maximum thickness where the drum or filter surface emerges or separates from the magma. Considerable difliculty has been experienced with the operation of prior types of rotary suction filters. owing to the piling up or massing of the solid particles or pulp at the point where the drum emerges from the magma container. This piling up or massing of the pulp in the container. seriously interferes with the adherence of the cake to the drum. lleretoiore the maximum possible pulp consistency which could be satisfactorily handled with rotary suction filters. has been approximately 1%, and inasmuch as it was necessary to dilute considerably tlieiiiagiiia coming from the digesters before it could be filtered, immense quantities of the liquor had to be handled through the filter drum. As a result of this dilution of the magma an increase in the capacity of the pumping apparatus was required. with a consequent increase in cost of operation. Owing to the tendency of the solid particles of pulp to separate when the magma is not in motion, it had been necessary, heretofore, to employ some form of agitating means, and mechanical agitators have been commonly employed for that purpose. It has also been found that when the drum travelled through the magma in the filter pan or container, there was a tendency for the magma to wash oft the pulp or solid particles which adhered to the filter surface of the drum. with the result that there was not only a piling up of the solid particles at the end where the drum emerged from the magma. but also a tendency to concentration of the pulp in 1923. Serial No. 636,365.

the magma of the container or pan instead of a proportionate filtering operation.

An object of the invention is to provide an improved method and apparatus for filtering. with which the capacity may be materially increased and the necessary dilution reduced to a minimum; with which mechanical agitators may be eliminated; with which the piling up or massing of the pulp at the end of the container where the drum emerges from the: magmais eliminated; with which concentration of the magma in the container is avoided; and with which a heavier cake may be satisfactorily handled by the drum.

A further object of the invention is to provide an improved filtering apparatus which will accomplish the above objects and which will be eflicient, durable, simple, and relatively inexpensive. Other objects and advantages will be apparent from the following description of an embodiment of the in vention and the novel features will be particularly pointed out hereinafter in claims.

In the accompanying drawings:

Fig. 1 is an elevation of a rotary suction filter which has been constructed in accordance with the principle of the invention;

Fig. 2 is a sectional elevation of the same taken substantially along the line 22 of l i 1;

fig. 3 is another sectional elevation of the same taken substantially along the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary sectional plan through a portion of the same. shown on a slightly largerscale, and taken substantially along the line 4--4 of Fig. 1;

Fig. 5 is a fragmentary sectional elevation of one. end portion of the drum, taken substantially along the line 5-5 of Fig. 4;

' Fig. 6 isa sectional elevation of the same taken substantially along the line 66 of Fi 4; i

' ig.'7 is a sectional elevation through a portion of the end of a drum showing details of the valve mechanism in one relative operative condition, the section being taken ubstantially along the line 77 of Fig. 5 but with the parts in a slightly different relative position;

Fig. 8 is a corresponding section with the parts in a difierent relative operative condition;

Fig. 9 is a fragmentary end elevation of a portion of the filter drum for the purpose of illustrating, on a slightly larger scale, certain of the details;

Fig. 10 is a sectional elevation of the same I taken substantially along the line 10-1O of Fig. 9;

Fig. 11 is another section of the same taken substantially along the line 11--11 of Fi 9; and

ig. 12 is another section of the same taken substantially along the line 1212 of Fig. 9.

In the illustrated embodiment of the invention a container 1 is provided with an arcuate bottom wall 2 having the, concave surface uppermost. The arcuate bottom wallextends to within a short distance of the upper edge of the container and together with the side walls of the container forms a pan or tank of the shape of a segment of a cylinder. The distance between the ends of the arcuate bottom wall 2 is less than the distance between the corresponding ends of the container 1 so that there will be an open chamber or compartment in the container at each end of the arcuate bottom wall. These chambers are designated by the reference numerals A and B. conduit 3 is connected to the container 1 so as to open into the chamber B, and through this conduit the magma to be filtered is supplied to the chamber B. The magma entering the chamber B rises and overflows the end edge of the arcuate bottom wall of the pan, the end edge serving as a weir for admitting the magma to the interior of the pan portion of the container. A suitable bailie 4 is disposed in the chamber B across the axis of the pipe 3 communicating therewith, so as to spread the incoming magma and insure a substantially uniform flow over the weir into the pan portion of the container.

The end of the arcuate wall 2 at the chamber A is provided with a vertically adjustable section 5 which serves as a discharge weir, and which may be elevated to difi'erent heights for controlling the level of the magma within the pan portion of the container. The liquid overflowing from the pan portion of the container into the chamber A, will be conducted through a suitable conduit 6 to a reservoir (not shown), from which it may be removed and recirculated, in suitable manner such as by pumps, through the conduit 3 and thence to the container. The direction of flow of the magma to and from the container is illustrated by arrows in Figure 3.

A. cylindrical drum or filter element 7 is mounted, by means of suitable ball bearing devices 8, upon the side wall 1** of the container for rotation about a horizontal axis. lhe axis of rotation of the drum or filtering element is substantially coincident with the center of curvattun cf the arcuete bottom reissues wall 2 of the container. A Worm wheel 9 is fixed upon one of the cylindrical end hubs 10 of the drum for rotation therewith, and is driven by a worm screw 11 which is carried by a shaft 12 that extends along the side of the container and is rotatably mounted in suitable bearings 13. The shaft 12 is provided at one end with a beveled gear 14 which meshes with a beveled gear 15 that is fixed upon a driving shaft 16. The driving shaft 16 is rotatably mounted in suitable bearings upon an end wall of the container and extends from side to side of the container. Suitable driving pulleys 17 may be provided upon one endof the shaft 16 for imparting rotation thereto and through it to the drum.

The drum 7, some distance from its outer peripheral edge, is provided with a peripheral wall 18, and suitable interchangeable grid sections 19 are disposed around the outer surface of the wall 18. The grid sections 19. at their ends, have inturned flanges 20 which abut against the wall 18 and space the grids therefrom for their entire length, so as to form between the wall and grids a plurality of filter compartments, there being a compartment for, each of the grid sections. The grid sections are slotted or otherwise perforated so as to allow the passage thercthrough of a liquid as will be hereinafter explained. Stretcher rods 21 pass between the opposite end walls of the drum and are countersunk into the corners at each pair of abutting ends of the grid sections. as shown particularly in Figures 9 and 10. The stretcher rods thus confine the grid sections to the drum and are held against endwise displacement by suitable nuts 22 threaded upon the ends thereof and having conical ends 23 which enter corresponding countersinks or recesses in the outer ends of the drum.

A filter screen or cloth 24 is wound peripherally around the drum over the grid sections 19 and beneath the stretcher rods, the stretcher rods serving to confine the filter screen against the grids and maintain it in a taut condition. The end walls of the drum are preferably slotted radially, as at 25, at the junction between each of the two grid sections, through which slots the stretcher rods may be passed against the filter screen and grid sections. After the rods have been inserted, the radial slots may be closed by filler blocks 26 having flanges 27 upon their inner faces, which flanges are countersunk into the abutting faces of the end walls of the drum. A screw 28, and a washer 29 therefor, of greater width than the slot 25, are secured to the outer face of each filler block so as to overlie the drum surface and clamp the filler block within its slot. A suitable gasket 30 may be interposed between the flanges 20 and against the wall 18 at each pair of abhtting sections, so as to be compressed between the two flanges and the wall 18 when the sections are forced by the stretcher rods against the wall 18. These gaskets 3O etl'cctively'close communication between the compartments formed between the grid sections and the wall 18.

Each hub 10 of the drum is provided across its interior with a partition 31 which has a plurality of apertures 32 arranged circularly about the axis of rotation of the drum. Pipes or conduits 33 enter these openings from the interior of the drum and are secured therein in any suitable manner such as by expanding the same in the openings. The pipes 33 connect these openings with the filter compartments formed around the periphery of the drum. There may be any number of filter compartments, but in the illustrated embodiment, there are twelve compartments formed by the twelve interchangeable grid sections. Two pipes 33 are connected to the opposite ends of each filter compartment, and extend to opposite ends of the drum. With this arrangement each compartment will be connected by a conduit to each end wall of the drum.

An annular wearing ring or plate 34 is secured u on the outer face of each partition 31- o the drum, and is preferably of hardened steel or other metal for the purpose of resisting wear, as will be hereinafter explained. Each of the:e plates 34 is provided with apertures or ports 35 which are aligned with the openings 32 and, in fact, form continuations of the same. An auxiliary port or groove 36 is provided in the outer face of each plate 34, extending inwardly in a radial direction as shown particularly in Figures 4 and 5. An annular valve plate or element 37, having a width substantially equal to the width of the annular plates 34, fits against each plate 34, with another annular plate 38 interposed between them. The plate 38 is secured to the valve late 37 in any suitable manner and is pre erably made of hardened steel or other metal to resist wear during relative rotation between the valve element 37 and the drum in a manner to be hereinafter explained more fully.

The plate 38 is provided upon its inner and outer circumferences with flanges 39 which run in corresponding grooves in the abutting face of the plate 34. Each element 37 is also provided upon its inner and outer circumferences with similar flanges 40 which tit into corresponding grooves in the abutting iace of the abutting plate 38, so that the plates 34 and 38 and element 37 w llby reason of the flanges 39 and 40, be positioned properly with respect to one another when brought together face to face. Each valve element 37 is provided upon its inner face with a plurality of arcuate recesses 41, 42

and 43 which are separated from one aninto the grooves or recesses 41, 42, and 43.

The ports or apertures 45, 46 and 47 are at such a distance from the axis of rotation of the drum that the drum ports or apertures in the abutting plate 34 will move into communication with them successively during rotation of the drum relatively to the valve element 37 and plate 38. A conduit 48 communicating with the aperture 47 extends outwardly from each valve element 37 and may be connected to a source of suction. Similar but smaller conduits 49 and 50 extend outwardly from each element 37 and communicate with the recesses 41- and 42 respectively.

The partitionsi-ll in the hubs of the drum are connected with one another by a concentrically arranged sleeve or tubular pipe 51 which passes through the partitions. A block or plug 52 is threaded into ,each end of the pipe 51, and a rod 53 is rotatable and slidable axially in each plug. Each rod 53 is provided at the end within the pipe 51 with a flange or head 54, and between it and the plug a helical compression spring 55 is disposed. These springs tend to shift the rods 53 inwardly into the pipe 51. A spider 56 is rotatably mounted upon the outer projecting end of each rod 53, and is held thereon in any suitable manner such as by a nut 57 and a washer 58. A washer 59 may be secured to the outer end faceof each.

spider 56 for rotation therewith. The washers 58 and 59 may have between them annular grooves forming a ball race for suitable ball bearings which reduce to a minimum the friction between them. A nut 57 is adjustable upon the outer end of each rod 53 so as to provide. by adjustment, various degrees of compression upon the helical spring 56. g

The arms of each spider 56 overlie the adjoining valve element 37 and clamp it. tightly against the outer face of the partition 31. The springs 55, pulling the rods 53 into the pipe, supply a yielding clamping. pressure upon the spiders 56. A yoke 60 is secured to each valve element 37 and is connected,by a pin 61, to a rod 62 which passes through a lug 63 that may be provided upon the bracket 13. Nuts 64 are threaded upon the rod 6:2 upon opposite sides of the car 63, so as to clamp the rod 62 in difi'erent adjusted positions. By adjusting the nuts 64 along the rods 62, the yokes 60 and valve elements 37 may be rotated, to a limited extent, about the axis of rotation of the drum. Each yoke and rod 62 thus holds against rotation with the drum, the valve element 37 and spider 36 to which it is connected.

Arcuate flanges 65 (Figs. 2 and 3) are provided upon the upper face of the arouate bottom wall 2 of the container, in substantial alignment with the side walls of the drum which extend radially outward beyond the filter screen 24. Resilient gaskets 66 are clamped by screws 67 and annular strips 63 to the flanges 65, so as to extend along and in contact with the faces of the projecting end walls and close the space between the flanges 65 and the drum. These gaskets 66 do not provide an absolutely tight joint but serve to effectively confine the solid particles of the magma to the channelbetween the peripheral surface of the drum and the arcuate bottom wall. This channel is substantially uniform in cross section throughout its entire length because the arcuate bottom wall 2 and the peripheral surface of the drum have substantially the same center or axis of curvature.

The upper surfaces of the ball bearings S are grooved lengthwise thereof so as to form tracks 67 in which the rollers 63 of the carriages 69 may run peripherally of the bearings. A suitable spray washer device 70 connects the carriages 69 and overlies the outer and upper surface of the drum, the spray device having pipes 71 extending lengthwise of the drum and provided with spray nozzles 72. The pipes are connected by suitable flexible connections 73 to sources of washing liquid (not shown). Each carriage 69 is provided with an arm 74 having a ball and socket or universal connection 7 to :1 depending rod 76, which at its lower end is connected through a universal connection 77 to a pin 78, carried eccentrically by a disc 79.

' One of the discs 7 9 is mounted upon an extension of the shaft 12, so that when the shaft 12 is rotated, the pin 78 will act as a crank pin and oscillate the carriage to which it is connected through the connecting rod 76. The other disc 79 (not shown) is mounted upon a shaft 80 which extends parallel with the shaft 12, but on the opposite side of the container. The shaft 80 is connected by bevel gears 81 and 82 to the shaft 16 so as to be driven therefrom concomitantly with the shaft 12. Thus when the shaft 12 is rotated, both discs 79 will be rotated, and by reason of the crank connections to the carriages 69 will oscillate the latter about the periphery of the ball bearings8 so as to carry the spray nozzles 72 over a portion of the periphery of the drum. When a liquid is supplied to the spray nozzles, through the pipe 71 and flexible conduit 73, the peripheral surface of the drum passing beneath the nozzle will be subjected to the spray wash.

A scraper or doctor plate 83 is mounted.

asaaoae in a suitable manner so as to run in close proximity to the screen or filter surface of the drum, at a point substantially on the horizontal diameter of the drum at the side where the drum enters the container during its rotation, for the purpose of removing the cake or layer from the filter screen.

The operation of the parts thus far described will now be given. Power is supplied to the shaft 16 through one of the pulleys 17, and through the shaft 12. screw 11, and worm wheel 9 this power will be utilized in causing a rotation of the drum about its axis in the bearings 8. The pipes or conduits 48 are connected to suitable suction creating devices and pipes 49 and are also connected to separate suction creating devices. The magma to be filtered is forced through the conduit 3 into the chamber B of the container. where it is spread uniformly by the bafiie 4. From the chamber B, the magma overflows the weir at the adjacent upper end edge of the arcuate bottom wall 2 and passes through the channel between the periphery of the drum and the arcuate bottom wall 2. The magma emerges from the channel between the drum and wall 2 at the opposite end. overflows from the vertically adjustable weir 5 into the chamber A. and is conducted through the conduit 6 to a suitable storage tank from which it may be subsequently withdrawn and recirculated through the conduit 3 and the container 1. The conduits 48 are in communication with the recesses 43 in the elements 37 at the opposite ends of the drum,and as the drum ports 35 in the plate 34 which are in alignment with the ends of the conduits 33, move past the ports a7. the suction created in the conduits 48 will be transmitted into the conduits 33 which are in communication therewith. Through these conduits 33, the corresponding compartments in the periphery of the drum which are formed between the grids and wall 18 of the drum, and in communication therewith, will have a partial vacuum created therein.

Each port 47'is disposed along the lower portion of the wear plate 38 so that the partial vacuum will be created in those compartments of the drum which at any time are wholly or partially (preferably wholly) within the container 1, and between the container 1 and the scraper. As each compartment of the drum enters the pan or container through which the magma is being circulated, the liquid portion of the magma will be drawn by the suction through the filter screen into the compartments and thence through the conduits 33 to the conduits 48 from which it will be conducted to suitable storage tanks. This suction will be continually applied to the compartments throughout an angular movement of the till titi

drum corresponding to the length of the ports 47. The ports d7 will preferably have such a length and position, that the main suction in each compartment of the drum is started as soon as the filtering surface of the compartment is completely or largely immersed in the magma, and terminated as the said surface begins to emerge from the magma. The reason for this is to reduce toa minimum the quantity of air drawn in with the main body of the liquor because the air increases the tendency of the liquor to loam or froth and the latter interferes with the operation of the pumps.

As the liquid portion of the magma is drawn through the screen and conducted to the storage tank, the solid portion of the magma which this liquid carried will be carried against the screen and'by the suction will be held thereon in the form of a layer or cake which adheres thereto during the continued rotation of the drum. As the drum ports 85 move heyondthe end of the slot or port M, the suction or vacuum created in the compartments to which they are connected will be broken, but immediately the ports will each move into communication with another elongated port- 46. The suction in the pipes will then he communicated to the recesses 42 and thence through the conduits 33 to the compartments to which theyare connected, so as to hold the cake or layer iirmly against the screen surface of the drum throughout a further angular movement of the drum. During this. angular movement, the wash liquid which is sprayed upon the upper suriace of the drum, will be drawn through the layer or cake into the compartments, which serves to wash the cake. The wash liquid which is thus drawn into the compartments will he conducted through the conduits 33 into the pipes 56 and thence to a suitable storage container (not shown).

As the drum ports 35 each move beyond the end of the relatively stationary port 46, the suction formed in the corresponding connected compartments will be broken and remain broken until the drum ports during further rotation of the drum move into communication with an arcuate port l5. The suction in the pipes 49 will then-be transmitted to the compartments through the recesses ll and ports 45, and a further quantity of the spray wash will he drawn through the cake or layer. Preferably, fresh water or washing liquid is supplied to the last two pipes 71 beneath which the calre passes and the liquid which is drawn from the conduits 4:9 is supplied to the other two spray pipes 71 beneath which the cake first passes. The fresh liquid will thus he used lor the final washing and the liquid from this final washing will he used for the first washing. In this manner the washing of the cake or layer is efiected with e um of washing liquid or water.

in the angular space between the ports 45 and 47 the valve elements 87 are provided with pipes 84: and 85 which pass on tirel t-herethrough. The plate 38, immediately between the pipes 84 and 85 at each end of the drum is provided with an aperture 86 which is divided by a partition 84, extending radially oi the drum. 'l ho halves of the aperture 86 are connected by grooves 88, formed in the plate 38, with the pipes 84 and 85, so that at each end of the drum the pipes 8d and 85 will be in communication with the adjacent halves of the aperture 86. The aperture 86 is disposed at a radial distance from the axis of rotation of the drum such that the grooves or auxiliary ports 36 formed in the face of the plate 3% that abuts the plate 38 will move beneath the same, successively during the rotation of the drum. As each port 35 passes beyond thev valve port t5, the suction which transmitted through this port 45 to the compartments will be broken and ediately the groove or auxiliary port 36 associated with this port 85 will move heneath the aperture 86. The hall of the aperture 86 which the groove 86 first reaches, co nicates with the pipe 84, and this pipe is open to the atmosphere so that any partial vacuum which may be still existing in the corresponding filter compartment be broken by the entrance of air.

During further rotation of the drum the groove 36 will move into counication with the other half of the aperture 86 and through it will he placed in communication with thepipe 85. lhe pipe 85' isconnected to a source of compressed air (not shown) and immediately that. connection is established therewith the compressed air will be forced into the corresponding compartment so as to loosen or dislodge the cake or layer which is carried thereon. The pipe 8% is provided with suitable one-way valve 89 such as a hall check valve (see It}, so that the compressed air will not escape to the atmosphere At the same time the valve 89 will permit of the entrance of air for the purpose of breaking the vacuum in the compartments as they pass successively toward the scraper 83.

lln the relative positions of the parts shown in Figure 7, one of the grooves 86 is in communication with thehalt' of the aperture 86 that leads to the vacuum release pipe 84 but has not yet reached the point where it connects with the source or compressed air.

in Figure 8, the parts are shown in the position in which a groove 86 is in counicalltl tion with the source of compressed air as well as in connection with the ipe 84. The aperture 86 is positioned so t at the compressed air is admitted to each compartment 48 while entering the container.

just before it reaches the scraper 83. By adjusting the yoke 60 in an angular direction the position of the aperture 86 can be varied slightly. This varies the point at which the cake is loosened from the screen for removal by the scraper.

During the rotation of the drum, the conduits from each compartment will move successively into communication with the pipes The suction created in the filter compartments at this time will be continued during the travel of each of the compartments through the container, and a new layer will be formed progressively thereon in the manner explained hereinbefore. With the conduits 33 connected to both ends of each-compartment, thcompartments can be completely emptltd by suction since there will be no blind pockets formed during the travel ofthe compartments. I

The magma is supplied to the chamber B more rapidly than the filter is able to handle it. and the excess will pass through the channel between the periphery of the drum and bottom wall 2 of the container and overfigw at the adjustable weir 5 and return to the storage or supply tank. It will be observed that the magma will travel through the channel between the drum and the container in the same direction as the periphery of the drum, and consequently there will be no skin friction on the drum which would tend towash off any of the adhering solid matter which had been drawn against the screen by the suction. By reason of the continued flow of the magma, there will be no piling up of the solid particles at the end where the drum emerges from the container. With the magma moving in the same direction as the drum, it is possible to increase the rate of linear travel of the drum filtering surface with a resulting increase in the capacity of the filter. By avoiding the piling up or washing off of the solid particles of the magma the consistency of the magma will remain practically constant.

The continued movement of the magma through the container will serve to keep the solid particles in suspension and uniformly distributed, and consequently the use of mechanicalagitators will be unnecessary. The magma is preferably supplied to the container at a-rate two or three times the ca-.

pacity of the filter, so that the travel of the magma in the channel between the drum and container will be at substantially the same rate as the lineir travel of the filtering surface 'of the drum.

It has been found by actual test that with a filter constructed in accordance with the principles of this invention, a magma of 2% or better consistency can be successfully han dled. By. using magna of a greater consistency the volume of liquid which it is neaepae necessary to handle is very greatly reduced, and the apparatus necessary to handle this liquid will therefore be considerably less than in the prior types of filters in which a magma of only 1% consistency can be handled.

While the illustrated form of the filter has been provided with the vacuum relief and compressed air pipes at both ends of the drum, it will be understood that they ma be prorided only at one end of the drum and still have a satisfactory apparatus. If desired, the conduits 33, which communicate with the forward ends of the filter compartments as the compartments enter the pan,-

may be omitted since the compartments will be thoroughly drained by the other conduits 33 which. as the compartments leave the pan, will be connected to the lower ends of the compartments. It will also be obvious that various other changes in the details and arrangements herein described and illustrated for the purpose of explaining the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. In continuous filtering the method which comprises producing linear travel of the filtering surface and passing a stream of the magi'na to be filtered in the same direction and in contact with said surface.

2. In continuous filtering the method which comprises producing linear travel of the filtering surface and passing a stream of the magma to be filtered in the same direction and in contact with said surface, the volume of the liquid supplied being greater than the-empacity of the filtering surface...

3. ln continuous filtering the method which comprises producing linear travel of the filtering surface and passing a stream of the magma to be filtered in the same direction and in contact with said surface, and at approximately the same rate of linear travel.

4. A continuousfilter comprising a container, a suction filter device hr ing a filtering surface .moving in said container, said device and container having cooperating walls defining a channel of approximately uniform cross section along a portion of the filtering surface, and means for introducing the liquid to be filtered to one end of the channel and for removing excess liquid from the other end of the channel, whereby when the liquid to be filtered is introduced into said channel in quantities in excess of the capacity of said filtering device said liquid will move as a stream along the channel and in contact with the filtering surface.

5. A continuous filter comprising a container, a suction filter device having a filtering surface moving in said container, said till device and container having cooperating Walls defining a channel of approximately uniform cross section along a portion of the filtering surface, and means for supplying liquid to be filtered to the end of the channel where the filtering surface starts its move ment therealong and for removing surplus liquid from the other end of the channel, W ereby when the liquid to be filtered is introduced into the channel inlet in quantities in excess of the capacity of said filtering device, the liquid in the channel will move as a stream along the channel and in the direction of the travel of the filtering surface.

6. A continuous filter comprising a container having a pan sectionprovided with an arcuate bottom wall, a suction filter drum carrying a filtering surface dip-ping into the said pan section, said drum and pan section having cooperating walls defining a channel along the filtering surface of approximately uniform cross section, and means for introducing the liquid to be filtered into one end of the channel and for removing excess liquid from the other end ofthe channel, whereby when the liquid to be filtered is introduced into said channel in excess of the capacity of said filtering surface, said liquid will move as a stream along the channel and in contact with the filtering surface.

7. A continuous filter comprising a container having a pan section provided with an arcuate bottom Wall, a suction filter drum carrying a filtering surface dipping into the said pan section, said drum and pan section having cooperating walls defining a channel along the filtering surface of approximately uniform cross section, and means for introducing the liquid to be filtered into the end of the channel where the filtering surface enters it and for removing excess liquid from the other end of the channel, whereby when the liquid to be filtered is introduced into the channel in excess of the capacity of said filtering surface within the channel, said liquid will move as. a stream along the channel and in contact with and in the same direction as the filtering surface.

8. A continuous filter comprising a pan having an inlet at one point and an outlet at a point distant therefrom, a rotary suction filter drum mounted for rotation with its filtering surface dipping into the pan, said drum and pan cooperating with one another to form a relatively small channel of approximately uniform cross section extending along the filtering surface of the drum between the inlet and outlet, whereby a continuous stream of the magma to be filtered may be passed through the channel in contact with the filtering surface, and means for rotating the drum to carry its filtering surface in the same direction as the magma stream.

9. A continuous filter comprising a pan of the form of a segment of a cylinder with weirs at the ends of the arcuate wall, conduit means connecting with the pan for supplying to one end of the pan over the weir, the magma to be filtered, means for remov ing excess magma \vliiclr overflows the weir at the other end, a suction filter drum mounted for rotation with a portion of its filtering surface dipping into the pan below the level between the weirs, means extending between the pan and drum for confining the magma in the pan to the space between the filtering surface and the arcuate bottom wall of the pan.

10. A continuous filter comprising a pan of the form of a segment of a cylinder, a suction filter drum mounted for rotation above the pan and dipping into the pan with the center of curvature of the drum periphery substantially coincident with the center of curvature of the arcuate wall of the pan, said drum having a porous filtering peripheral wall, flanges extending along the arcuate wall of the pan in a peripheral direction, and gasket means acting between the flanges and the lateral walls of the drum for forming a closed channel between the drum and arcuate wall, means for rotating the drum to carry the filtering surface continuously through the pan, and means for admitting the magma to be filtered to one end of the closed channel and removing it from the other.

11. A continuous filter comprising a pan of the form of a segment of a cylinder, a suction filter drum mounted for rotation. above the pan and dipping into the pan with the center of curvature of the drum peripher substantially coincident with the center of curvature of the arcuate wall cf the pan, said drum having a porous filtering peripheral wall, flanges extending along the arcuate wall of the pan in a peripheral diill?) rection, and gasket means acting between drum and ,arcuate wall, means for rotating the drum to carry the filtering surface tinuously through the pan, and means r admitting the magma to be filtered the end of the closed channel where the drum periphery enters the pan, and for removi excess magma at the opposite end of channel,

12. In continuous filters, a frame, a filter drum carried by said frame for rotation about a substantially horizontal axis, said drum having suction filter compartments arranged around its periphery, with conduits leading from said compartments and opening through an end wall of the drum, a valve device held against the end well 0% abuts the end wall of the drum, which chamhers communicate each with a number of the conduit openings which move successively into communication therewith asthe drum rotates relatively thereto, and suction pipes connected to each of said chambers whereby the filter liquor and wash liquor which are drawn into the filter con1part-.

ments during difierent portions of therotation of the drum may be kept separate, said valve device being provided with an air vent and a compressed air conduit into communication with which the conduit openings of the drum move successively as the drum rotates, whereby the vacuum in each filter compartment may be first broken and then subjected to compressed air to loosen the filter cake from the drum.

13. in a'continuous filter. a rotary filter drum having end walls, a tubular pipe extending between said end walls, ports in one of said end walls, a valve device fitting against the said oneend wall and over the ports therein to control communication with said ports, means including a resilient device in said pipe for clamping the valve device yieldingly against said one end wall, means for holding the valve device against rotation with said drum, litter compartments carried by the drum, and means connecting said con'ipartments with the ports.

14:. In a continuous-filter, a rotary filter drum having filter compartments, and also ports in a drum surface with which the compartments communicate, a relatively stationary valve device engaging said drum surface over the ports and having means by which suction can he created successively in the compartments through said ports for given angular movements of the drum, said valve device having air vent and compressed air supply portswhich are disposed in succession within the path of the ports as the latter rotate with thedrum whereby the compartments will, at a certain point in the rotation of the drum where suction is not created therein, be opened to the atmosphere and then subjected to compressed air.

In witness whereof, I hereunto subscribe my signature.

WILLIAM D. MOUNT. 

